Dr. O^Bryen Bellingham on Irish Entozoa. 167 



XXII. — Catalogue of Irish Entozoa, with observations. By 

 O^Bryen Bellingham, M.D., Fellow of and Professor of 

 Botany to the Royal College of Surgeons in Ireland, Member 

 of the Royal Zoological, Geological and Natural History So- 

 cieties of Dublin, &c. 



[Continued from p. 105.] 



Order 1. NEMATOIDEA. 



Genus 8. Ascaris. 



(Derived from aaKapi^w, salio.) 



Body cylindrical and elastic, attenuated more or less at the extre- 

 mities. Mouth terminal, provided with three tubercles, one of 

 which is superior, two inferior. Anus a transverse cleft close to 

 the posterior extremity. Male organ a double spiculum without 

 any sheath. Female organ opening externally about the junction 

 of the anterior with the middle third of the body. 



The name Ascaris was given to this genus by Linnseus on ac- 

 count of the liveliness of the motions of some of the species, and 

 it has been adopted by all zoologists since. The species are very 

 numerous, 140 being enumerated by Rudolphi in his ' Synopsis.' 

 They occur in mammalia, birds, reptiles and fish ; their most 

 common habitat is the alimentary canal. 



Rudolphi has made three divisions of the genus. 



The first contains the species which are equally attenuated at 

 each extremity. 



The second, those in which the anterior extremity has a greater 

 diameter than the posterior. 



The third, those in which the posterior extremity has a greater 

 diameter than the anterior. 



Each of these divisions Rudolphi has again subdivided accord- 

 ing as the head is provided with lateral membranes (what he 

 calls winged), or as this part is naked or destitute of these ap- 

 pendages. 



Corpore utrinque cequaliter attenuate ; capite nudo, 

 1. Ascaris lumbricoides*. Small intestines of man (Homo). 



* The Ascaris lumhricoides (or common round worm of the human 

 intestines) has been known longer than any other species of Ento- 

 zoon ; it is included in Pennant's and Turton's list of the British 

 species ; it is not peculiar however to the human subject, for it oc- 

 curs also in the intestines of the ass, wild-boar, pig and ox : the spe- 

 cies found in the horse, although for a long time confounded with it, 

 and resembling it in some points, is now known to be distinct. 



The Ascaris lumhricoides inhabits the small intestines of the human 

 i«ubject ; the female is much larger than the male, and is much nwre 



